Logic Masters Deutschland e.V.

Zetamath recently hosted a setting challenge for setters to submit octoquadris. My original submission had some issues which I decided to go back and fix before publishing. I hope you like it.

Rules:
- Within the left U-bahn grid, draw a totally connected loop network through the centers of some cells, which may branch or turn, but may not have any dead ends.
- A clue outside the U-bahn grid indicates how many times the corresponding line shape (i.e. a cross, branch, straight line, turn) appears in the corresponding row or column, irrespective of the line shape's rotation.
- In the U-bahn grid, assign each line shape (irrespective of rotation) a digit from 1-4 as follows: corner=1, straight line=2, branch=3, cross=4.
- In the right Octoquadri grid, place eight of the digits from 1-9, twice each in the grid, such that no digit appears more than once in each row, column, or 2x2 region. Digits along a green german whisper line must differ by at least 5.
- Each cell in the Octoquadri grid corresponds to a 2x2 region in the U-bahn grid. Digits in the Octoquadri grid indicate the the sum of U-bahn 'digits' in the corresponding U-bahn region.


Solve on Penpa+
Solve on SudokuPad (no answer check)